1. Field of the Invention
The present invention relates to the arbor mounting hole structure of circular saw blades. More particularly, the present invention relates to circular saw blades that have arbor mounting holes that can be attached to diverse cutting machines having asymmetrical drive arbor configurations.
2. Prior Art Description
There are many types of cutting machines that utilize circular saw blades. Circular saw blades are typically round blades that have cutting teeth along the periphery of the blade. Traditionally, an arbor mounting hole is disposed in the center of the blade. The arbor mounting hole passes over a rotating drive arbor of the cutting machine, thereby interconnecting the drive arbor of the cutting machine to the circular saw blade. The interconnection of the blade arbor mounting hole with the drive arbor of the cutting machine serves two purposes. First, the interconnection of the drive arbor with the blade arbor mounting hole centers the blade so that the blade is balanced when it spins. Second, the interconnection of the drive arbor with the blade arbor mounting hole enables the drive arbor to turn the blade.
The most common type of arbor mounting hole used on a circular saw blade is a round hole that is located in the geometric center of the circular saw blade. Such arbor mounting holes pass over round cutting machine arbors that have a diameter close to that of the blade arbor mounting hole. In such round arbor mounting hole blades, any blade that has a round arbor mounting hole of the proper diameter can be mounted on the cutting machine.
In certain applications, non-circular arbors are used on cutting machines to provide a more positive connection between a circular saw blade and the rotating arbor. By using non-round arbors on the cutting machine and non-round arbor mounting holes in the blades, the blades are prevented from rotating around the arbor, should the saw blade bind on the material it is cutting. Such non-round arbor mounting holes are typically symmetrically disposed around the geometric center of the circular saw blade. Circular saw blades with symmetrical square-shaped arbor mounting holes are exemplified by U.S. Pat. No. 3,869,795 to Treace, entitled, Cutting Blade For Use With An Oscillating Cast Cutter; U.S. Pat. No. 4,706,386 to Wiley, entitled Quick Change Mechanism For Diamond Arbor Circular Saw Blades And Other Spinning Disc Devices; and U.S. Pat. No. 2,822,648 to Metzger, entitled Rotary Tool Mounting And Method Of Assembling The Same.
Circular saw blades with symmetrical diamond shaped arbor mounting holes are exemplified by U.S. Pat. No. 2,795,247 to Topolinski, entitled Reversible Circular Saw; and U.S. Pat. No. 2,649,868 to Gommel, entitled Mounting Rotors on Arbors of Various Transaxial Contours.
In the wide cross-section of industry that produces cutting machines, some companies have developed cutting machines with asymmetrical drive arbors that are proprietary to the manufacturer. Such asymmetrical drive arbors only accept circular saw blades having arbor mounting holes that are specifically manufactured for that cutting machine. Accordingly, a customer must purchase specialized blades from a specific manufacturer in order to utilize the cutting machine manufactured by that manufacturer. In many instances, the arbor mounting hole on such blades is an asymmetric triangle. Such a configuration is found in U.S. Pat. No. 5,477,845, to Zuzelo, entitled Saw Blade And Mounting Means For The Same. Other blades have arbor mounting holes that are combinations of straight sides and curved sides. Such prior art blades are exemplified by U.S. Pat. No. 2,572,042 to Martin, entitled Means For Mounting Cutting Blades On Shafts; U.S. Pat. No. 5,603,310 to Chiuminatta, entitled Mounting Arbor For Saw Cutting Blades; U.S. Pat. No. 5,373,834 to Chiuminatta, entitled Mounting Arbor For Saw Cutting Blades; U.S. Pat. No. 5,303,688 to Chiuminatta, entitled Mounting Arbor For Saw Cutting Blades; and U.S. Pat. No. 5,660,161 to Chiuminatta, entitled Mounting Arbor For Saw Cutting Blades.
A problem with asymmetrical arbors is that the blade that fits on such a specialized arbor only fits in one direction. Due to the asymmetrical shape of the arbor, the blade cannot be flipped and remounted. Saw blades with asymmetrical mounting holes are therefore limited to rotate in a single direction.
With many styles of saw blades, a contractor often reverses the direction of the blade. In many circumstances the ability to turn a blade can double the life of the blade. A need therefore exists for a circular saw blade that can fit onto an asymmetrical arbor, yet can also be flipped and readily mounted to that same asymmetrical arbor. This need is met by the present invention as described and claimed below.